What custom software actually costs

If someone asks "how much does an ERP cost?" and answers with a single number, you are talking to someone who has not yet understood what you are about to do.

Price is a function of complexity, not of pages

Custom software costs in proportion to how many different things it has to do well. Ten screens writing to one database is a project. Ten screens that must talk to accounting, the warehouse and a supplier ERP is a project an order of magnitude apart.

The four components of an estimate

**Domain and specifications.** How many people, how many roles, how many permissions, how many business rules to encode.

**Integrations.** Every external system adds authentication, data mapping, error handling and maintenance. This is the line that always gets underestimated.

**Quality.** The price of a test running on every commit is far lower than the price of an incident in production. Quality is not an extra: it is a budget decision.

**Compliance.** Auditing, traceability, GDPR and data retention impose architectural decisions that must be taken at the beginning, not at the end.

Why we insist on sprints

A fixed price only makes sense when the requirement is stable, and in a new project it almost never is. We work in sprints, estimate each one, and update the forecast every two weeks with real data instead of January's hopes.

If a fixed-price offer appeals to you, ask what happens if in the third month you discover you also need digitally qualified signatures. Whoever answers "we had not thought of that" is already telling you the price is a bet.

The practical advice

Always ask for three numbers: the cost per sprint, the total estimated cost at the end of the project, and the conditions that change that estimate. If a supplier cannot answer, the project is riskier than you imagine.